It really depends on your tech stacks. Running python on the backend and JS on the frontend will create enough impedance mismatch to indeed make server-side rendering of react rather difficult.

Clojure's reagent and re-frame remove most of the complexity and tools from the equation. You run the same (mostly) code on the backend and frontend. This is what I meant by quite easy :)

http://davidtanzer.net/server_side_rendering_with_re_frame http://yogthos.net/posts/2015-11-24-Serverside-Reagent.html